<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>导航</title>
</head>
<frameset cols="120,*">
    <frame src="./上机3.html">
    <frame src="./上机3.1.html" name="a">
</frameset>

<!-- 特殊情况 -->
<noframes>
    <body>
        <p>浏览器暂不支持，frameset 请升级浏览器</p>
    </body>
</noframes>
</html>